The present invention relates to antenna connectors and more particularly but not exclusively to antenna connectors for snap-fitting into a casing.
Devices that require antennas include one and two-way radios and mobile telephones. The devices include casings and generally require than an antenna is connected electrically through the casing to circuits inside and is also firmly attached mechanically to the casing such that the antenna cannot accidentally be removed due to longitudinal or shear forces. In addition it is desirable that intentional removal of the aerial be relatively easy.
A conventional mobile telephone and typical prior art antenna are shown in FIG. 2. A stubby antenna 2 has a snap-fit connection comprising a latch 4 at a lower end to enable it to be pressed into a casing 12 of a mobile telephone 10. The latch 4 comprises an arm 6 and a latch head 8. The arm 6 bends inwardly as the antenna 2 is pressed downwards through a hole in the casing 12 to allow the latch head 8 to pass therethrough. Due to the resilience of the arm 6 the latch head 8 springs outwardly on the far side of the hole to fix the antenna 2 in position.
A disadvantage of the antenna is that in order to remove the antenna without risk of breaking the latch, 4, it is necessary to remove the casing so that the latch 4 can be pressed inwards. Furthermore, if a sharp upward force is applied to the antenna 2 there is a strong risk of breaking the arm 6 and thus accidentally removing the antenna. The risk is increased because the arm 6 may in any case be weakened to make it flexible. If the arm 6 is broken it will be appreciated that the antenna 2 cannot be snapped back into place and the mobile phone may be returned by the customer for servicing.
In accordance with a first aspect of the present invention there is provided a connection mechanism for snap-fitting an antenna bushing extending along a first direction to a receptacle having an opening reaching from a first end to a second end, wherein a latch, including a stem and a latch head, extends around a circumference of the antenna bushing, in a plane substantially perpendicular to the first direction, which latch is inwardly depressible to a depressed position within the circumference to allow insertion of the antenna bushing into the opening from the first end and is able to return to a non-depressed position to retain the antenna bushing against the second end.
Preferably, the latch is mounted on a sleeve and further including a rib extending around the antenna bushing, the rib being located so as to underlie the latch when the sleeve is placed on the antenna bushing to abut against the rib.
Preferably, the rib is mounted on the antenna bushing.
Preferably, the sleeve is rotatable when latched to the receptacle to push the latch against a protrusion on the second end to depress the latch into the depressed position, thereby to extract the antenna bushing from the receptacle.
In one embodiment the connection mechanism may include an anti rotation device for preventing rotation of the sleeve when the antenna bushing with the sleeve placed thereon, is latched to the receptacle. Such an embodiment may require the case to be removed in order to allow the antenna bushing to be extracted.
Preferably, the anti-rotation device includes a protrusion on an outer surface of the sleeve adapted to fit within a corresponding groove in the receptacle.
According to a second aspect of the present invention there is provided an antenna bushing held in a first direction and connected to a 2-way transmitter device by a connection mechanism, the connection mechanism including a receptacle having an opening reaching from a first end to a second end, wherein a latch, including a stem and a latch head, extends around a circumference of the antenna bushing, in a plane substantially perpendicular to the first direction, which latch is inwardly depressible to a depressed position within the circumference to allow insertion of the antenna bushing into the opening from the first end and is able to return to a non-depressed position to retain the antenna bushing against the second end.
Preferably, the latch is mounted on a sleeve and further including a rib extending around the antenna bushing, the rib being located so as to underlie the latch when the sleeve is placed on the antenna bushing to abut against the rib.
Preferably, the rib is mounted on the antenna bushing.
Preferably, the sleeve is rotatable when latched in the receptacle to push the latch against a protrusion on the second end to depress the latch into the depressed position, thereby to extract the antenna bushing from the receptacle.
In an alternative embodiment, the connection mechanism includes an anti-rotation device for preventing rotation of the sleeve when the antenna bushing with the sleeve placed thereon, is latched to the receptacle.
Preferably, the anti-rotation device includes a protrusion on an outer surface of the sleeve adapted to fit within a corresponding groove in the receptacle.
According to a third aspect of the present invention there is provided a connector for latching an antenna holder to a housing, wherein the holder is adapted to hold an antenna to extend in a first direction, which connector is adapted to fit into the housing, wherein the holder fits into the connector and wherein the connector includes a circumferentially extending latch for latching the holder.